anorthosite

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anorthosite

[ə′nȯr·thə‚sīt]
(petrology)
A visibly crystalline plutonic rock composed almost entirely of plagioclase feldspar (andesine to anorthite) with minor amounts of pyroxene and olivine.
References in periodicals archive ?
The silicic features we've found on the Moon are fundamentally different from the more typical basaltic mare and anorthositic highlands," said Timothy Glotch of Stony Brook University, N.
Mineral variation in anorthositic, troctolitic, and adamellitic rocks of the Barth Island Layered Structure in the Nain Anorthosite Complex, Labrador.
PGE mineralization within this area along the eastern side of the SKI and within the adjacent anorthositic rocks on the East Shore Property was previously reported in the Company's February 5, 2013 press release.
3c), olivine gabbronoritc, and anorthositic gabbro all included in the olivine gabbro unit of the pluton.
They include most plutons known in the Brookville terrane; exceptions are orthogneissic components of the Brookville Gneiss, the Gaytons Granite, and subsurface gabbroic, anorthositic, and granitic rocks of the Lower Coverdale Gabbroic Complex.
The TAZ1 zone in Hole IC-01-04 is characterized by highly variable cumulate layers, which include four olivine-bearing cycles and several anorthositic zones.
Magmatic layering in mafic to ultramafic rocks is well preserved in layered intrusions, while discordant mafic layered plutons in the northeastern part of the complex area vary in composition from medium- to coarse-grained anorthositic gabbro to plagioclase porphyritic gabbro.
Much of the core shows extensive alteration but microprobe analyses of fresh samples revealed that the plagioclase in both anorthositic and gabbroic rocks has a fairly uniform andesine composition.
All samples were taken randomly from gabbroic, anorthositic and felsic-rich rocks of the East Bull Lake Intrusion over an area approximately 200 meters long by 50 meters wide.
Miller also identified aerially extensive gabbro-anorthosite plutons on both sides of Ferguson Lake, and has discovered disseminated base metal sulphide mineralisation with anomalous PGM values hosted by anorthositic gabbro on the east side of Ferguson Lake.
A petrological study of the Lower Coverdale ferrogabbro complex has not been published, but it appears to contain a large component of anorthositic rocks (Boyle and Stirling 1994; Woods 1995; Ascough 1997) that are not present in the Caledonia Mountain Pluton, at least not at the present level of exposure.
Mr French also advises that the vertical drill hole which is presently at 3050 feet has cut anorthositic rocks.